River Basin Information Systems Meeting
Nairobi – Kenya
13 – 14 February 2002
Water Resources of Mozambique
“ and the situation of the shared rivers”
Prepared by
Dr. Francisco Tauacale
Lecturer in water Management
Eduardo Mondlane University
Department of Geography
Catedra de Homem e Meio Ambiente
Campus Universitário 2 andar 308
e-mail: Gualerosa@yahoo.com
Water Resources of Mozambique
“ and the situation of the shared rivers”
1. Bref characterization of the country
Mozambique lies on the East Coast of Africa between the parallesls 10º 27’ and 26º 52’ of south latitude and the
meridians 30º 12’ and 40º 51’ west longitude. The country has a land border os 4,330 km and a coastline of 2,470
km. The land area is 799,380 km2, including 13,000 km2 of inland water. The country is bordered on the north by
Tanzania, on the west by Malawi, Zambia, Zimbabwe, Republic of South Africa (Transvaal) and Swaziland, and
on the south by the Republic of South Africa (Natal).
2. Rivers Basins
Most of the rivers in Mozambique flow in a W-E direction, draining the water of the central african high plateau
into the Indian Ocean.
Mozambique has 104 identified rivers basins, considering only catchments of rivers that flow into the Indian
Ocean. The coastal zone is considered as one catchment. (Consultec, 1998)
With the exception of the small rivers draining the coastal zones, the majority of the rivers have a torrential
reigime, with high waters during 3-4 months and low flows for the remainder of the year corresponding to the
marked wet and dry seasons.
The southern basin until Save are mostly formed the terminal reaches of the international rivers, such as the
Maputo, Umbeluzi, Incomati, Limpopo and Save. They are characterized by low runoff coefficients, deep saline
intrusion in the mouths ( reaching up to 50 km inland) wide and shallow rivers valleys with low storand
consequent high evaporation losses and large flood-plane areas.
In the center of the country, the river basins are almost entirely within Mozambique, rising on the border
mountains and decreasing gradually in altitude until the sea where also intense saline intrusion occurs. These rivers
have more permanent runoff as compared with the southern ones, not only because of the different climatic regime
of the regions but also because of increasing upstream abstractions on the international southern river basins.
The northern rivers, except for the Rovuma, originate from the plateau and mountains out of Mozambique, we
have Lurio, Licungo, Messalo and Ligonha. Up north, the Rovuma rivers forms the border with Tanzania. (Atlas,
1998)
Areas of river basins in Mozambique:
Area (Km2)
N. Basins
Source: DNA 1998
< 1,000
50
1,000 – 10,000
40
10,000 – 100,000
12
> 100,00
2
Two river basin which occupy in Mozambique more than 100,000 Km2 are the Zambezi (140,000 km2) and the
Rovuma (101,200 km2)
The basins with more than 10,000 km 2 in Mozambique are besides Zambezi and the Rovuma ones and excluding
the coastal zone ( which is not a river basin) . by decreasing order of areas in Km2. Limpopo (79,600) Lurio
(60,800) Pungue (28,000) Licungo (27,700) Buzi (25,600) Messalo (24,000) Ligonha (16,300) Incomati
(14,900) Gorongosa (13,200), Inharime (11,900), Govuro (11,200) (DNA, 1999)
Same other river basin deserve mention, althoug their areas in Mozambique are smaller than 10,000 km2. Maputo,
Umbeluzi, Save, Monapo and the Montepuez basin.
The total area in Mozambique of these 18 rivers basins is about 572,500 km2, more or less 75% of the total area of
Mozambique.
11 river are more than 300 km long in Mozambique. They are the Zambezi ( 850 km), Limpopo (560 km), Save
(330 km), Buzi (320 km), Pungue (320 km), Licungo (336 km) Molocue ( 325 km), Lúrio ( 605 km) Montepuez
(315 km), Messalo ( 530 km) and Rovuma ( 650 km). (DNA,1999)
From the 18 main river basin that have been presented, 9 are shared with other countries:
Maputo: RSA and Swaziland
Umbeluzi: RSA and Swaziland
Incomati: RSA and Swaziland
Limpopo: RSA, Borswana and Zimbawe.
Save: Zimbabwe
Pungue: Zimbabwe
Zambezi: Angola, Namibia, Botswana, Zambia, Zimbabwe, Malawi and Tanzania
Rovuma: Tanzania
The figure represents the position of Mozmbique in the shared river basins. With the single exception of the
Rovuma, Mozambique is located at the downstream end of all the basins. This puts Mozambique in a vulnerable
position as water developments in the countries located further upstream will tend to decrease the water flows to
Mozambique while at the same time increasing the problens of water quality.
Dimension od the problem:



52% of the Mozambique territoty is located in internacional river basins but Mozambique represents only
20% of the total area of these basins;
more than 50% of the surface water of the country are inflows at the border.
Almost 50% of the surface water resources are concentreted in the Zambezi (international) river basin.
The management of these shared river basin and reaching agreements with the other riparian countries on water
sharing and integrated water resources management is thus a priority for Mozambique.
2.2. The sitution of the principal rivers
2.2.1.
The Maputo basin:
Crosses an area of very rich bio-diversity, having been recognized as such by UNEP and included as one of the
world’s conservation areas.
2.2.2.
Umbeluzi:
Shared with Swaziland – water supply for the capital Maputo , A dam (Pequenos Libombos)built in the 1980.
Irrigated agriculture exists: In swaziland – large scheme and in Mozambique smallrs scheme. Both countries have
signed an agreement for water sharing but this agreement is not favorable to Mozambique while also being
technically very insufficient.
2.2.3.
Incomati:
Shared with RSA and Swaziland.
Incomati is a basin, whose water is intensively used in RSA mainly for irrigation. Mozambique has also some
important irrigation schemes. However, the flows in the main river have been very much reduced in the last 15
years. Now we have the salt intrusion problem.
2.2.4.
Limpopo:
A large river basin where is located the largest irrigation scheme of Mozambique (Chokwé). However, the
intensive use of water in the upstream countries, especcialy in Zimbabwe and RSA, reduced very much the flows
entering in Mozambique. The river is now dry during 3 or 4 months in a normal year, a situation that has never
occurred before 1980. Problems of water quality at the border inflows are also being felt.
2.2.5.
Save:
Large basin. During the 1980s, zimbabwe went on with an intensive program for use water resources of the basin.
As a result, the Save is now almost permanent dry.
2.2.6. The Zambezi
The largest river basins in Africa and the most important one in Mozambique. It concentrates about 50% of the
surface water resources of the country and about 80% of its hydropower potential. The Cahora Bassa dam, one of
the largest reservoirs in the world, was built in the mid – 1970s for power production. Irrigation was developed in
the Lower Zambezi, especially sugar cane. There are projects to expand the power capacity of Cahora Bassa and
built another dam further downstream, Mepanda-Uncua.
The other basins north of Zambezi are not much developed in terms of water use, being limited to some urban
supplies and small scale irrigation.
3. Surface water
The surface water are the country’s main water resource. Mean annual runoff is estimate at 216,000 mililion cubic
metres (Mm3), of which only 100,000 Mm3 originates in rainfall inside Mozambique. The remainder originates in
countries upstream, which is why this figure has been falling with the increased use of water in these countries.
In terms of the geography distribution, five regions have been identified, bringing together contiguous river basins
and they will be administered by the Regional Water Administration (ARAs), set up by the water law:
 ARA – South – includes all the basins south of the Save, and the Save river basin itself.
 ARA – Centre – covers all the basins between the Save and Zambezi basins.
 ARA – Zambezi – corresponds to the Zambezi river basin.
 ARA – Centre-North – covers the zambezi basin as far as Lúrio river, including the Lurio basin.
 ARA – North – Covers all the basin north of the Lurio basin.
Table 2. Characterstics of the regions covered by the ARAs.
Region
Area
(1,000 km2)
Mean annual runoff (km3)
Flow
at border
Generated in
Mozambique
Mean annual runoff (mm)
Total
Flow Generated in Total
at border
Mozambique
South
Centre
Zambezi
Centre-north
North
192
84
140
196
168
17.0
1.2
88.0
0.0
10.0
3.8
18.4
18.0
35.2
24.9
20.8
19.6
106.0
35.2
34.9
89
14
629
0
60
20
219
129
180
148
109
233
758
180
208
Total
780
116.2
100.3
216.5
149
129
278
Source: Carmo Vaz, 1999
From the tables, one notes that the southern region is entirely dependent on the basin of international rivers.
Mozambique is very dependent on water made available by the countries upstream, particularly in the southern
region, where more than 80% of the mean annual runoff is received from neighbouring upstream countries.
4. Hydrometeorological networks and data processing
Hydrometeorological data is an essential requirement for water resources management, basides others uses in
fields like applied hydrology, agriculture, ecology and so on.
In Mozambique, rainfall and evaporation are measured by various institutions, mainly public ones – DNA, INAM
and INIA –but also by some private bodies like agricultural enterprises, the other variables are only measured by
DNA or related bodies like the ARAs. HCB and EDM measure levels and discharges at Cahora Bassa and
Chicamba dams.(DNA, 1999)
4.1. Rainfall network
Measured by DNA, INAM, INIA. Same agricultural enterprises like “Sociedade agricola do Incomati”.
Measurements of rainfall started in 1908. We have a lot until 1975 , INAM and DNA. After the independence,
there was a significant decrease in the number of stations in operation.
Table 3. Evolution of the rainfall network
Institution
1975
DNA
341
INAM
155
INIA
15
Total
531
Source: DNA, 1999
1982
269
149
15
433
1996
78
44
4
127
4.2. Evaporimetric network
INAM, INIA and DNA measure evaporation in a limited number of stations
In 1982, there were 30 evaporimetric station of INAM, 15 INIA and 4 of DNA. Nowadays INAM 18 stations,
INIA has 5 and DNA has 3, bringing the total to 26 stations.
4.3. Water levels and discharges
Only DNA measures water levels and discharges in rivers and reservoirs, in hydrometric stations. These
measurements are fundamental for the evaluation of the availability of surface water resources as well as for
studies of floods and other hydrological analysis (DNA, 1999).
Water levels are measured in scales, located at convenient points of the section. Usually, there is one reading per
day but during floods there are three or more reading per day.
Table 4. Evolution of the hydrometric network
Year
1975
1976
1981
Nr.stations
260
314
259
Source: DNA & Consultec, 1998
1982
231
1992
58
1996
76
4.4. Groundwater, water quality, sediment transport
Until now, DNA has not established a network for measuring groundwater levels, water quality and sediment
transport. Thess in terms of sampling points, sampling frequency and quality parameters to be analyzed. It has a
minimum network of 13 stations covering the rivers Maputo (2), Umbeluzi, Incomati (2), Limpopo (2), Save,
Buzi, Pungue and Zambezi (3). However, only 6 were functioning.(DNA,1998)
4.5. Data collection and processing by DNA
Acoding DNA (199), “before the creation of ARAs, the country was divided in 11 hydrometric sectors”, which in
most of the cases coincided with the provinces. Now the ARAs are being established and the hydrometric sectors
will be controlled gradually by then.
In each hydrometric sector, there are readers (leitores) who are responsible for reading.
5.
Conclusion
The management of these shared river basin and reaching agreements with the other riparian countries on water
sharing and integrated water resources management is thus a priority for Mozambique.
If we need agreements, in the short term, one of the main priorities is the recovery and later expansion of the
hydrometeorogical network, while at the same time modern technologies are introduced for data collection,
transmission and processing.
The problem from the water resources management is:
- floods and droughts are part and parcel of the rivers of the region.
- In vast area of the interior of south -centre of Mozambique (Incomati, Umbeluzi, Limpopo and Pungue) has
loss land, caused by salt-water intrusion, resulting from the low discharges of effluents
- Loss of bio-diversity, resulting from the low discharges of effluents
6. References
Carmo vaz, A. Recursos hidricos de Moçambique, potencial, problemas politicos, associaçao Moçambicana de
ciencias e tecnologia, Maputo, 1999.
DNA, Programa Sectorial de Investimentos do sector da Água. Direcçao Nacional de Águas, Maputo, 1998.
DNA, Country situation Report. Direcçao Nacional de Águas, Maputo, 1998.
DNA, Provincial Towns water sector study DHV/Consultec, Maputo, 1995
DNA, Water resources of Mozambique, 1999